Steering mechanism



Oct. 23, 1928.

s. R. w. 'M. B'AGER STEERING MECHANISM Original Filed May 2; 1923 2Sheets-Sheet m k RIM/15 2;.

INVENTOR;

ATTORNEYS.

Octi 23, 1928.

S. R. W. M. BAGER STEERING MECHANISM A TTORNEYS.

Fatented Oct. 23,1928.

(UNITED STATES PATENT OFFICE."

SVAH'IE B. W. M. BAGER, OF SOUTH MILWAUKEE, WISCONSIN, ASSIGNOB TOBUC'YBUS- ERIE COMPANY, OF SOUTH MILWAUKEE, WISCONSIN, A CORPORATION OFDELA- WABE.

original application filed May 2, 1923,

ilhis case is a division of my oopending application, Serial No.636,137, filed on May 2, 1923, which contains generic claims coveringboth theshowing of this present application and the showing of theparent case; also claims coverin the outside clutch-lever feature shownin igures 1 and 2 of the present case.

This invention relates to'steering mocha to nism for power excavators,cranes and the like, in which the upper or head frame, carrying theoperating parts, is revolvable with respect to the base or truck frame.

In machines ofthis character, direct connections have heretofore beenemployed between thehead frame and steering axle, in the case of wheeltraction, or between the head frame and appropriate clutches on thedriving shaft, in the case of creeping traction, 29 so that steeringmovements are dependent upon and responsive to actual rotation of thehead frame.

' The general aim of the present invention is the provision of steeringmechanism which 2% is not dependent for its operatidn upon the rotationof the head frame, but in which steering is efiected rather by theselective application of power derived from the mechanism ordinarilyemployed for rotating the frame.

A more specific object is the provision of steering mechanism which maybe made to respond to rotation of the swing pinion ordinarily employedas part of the head frame rotating mechanism, without rotatingthe headframe.

Other objects and advantageswill appear from the following descri tionof several illustrative embodiments o the invention.

in the drawings:

Figure 1 is a plan view of the truck frame of a power excavator equippedwith a steering mechanism constructed in accordance with the presentinvention.

Figure 2 is a view in side elevation, partly in section, of the machineshown in Figure 1.

Figure 3 is a side elevation, partly in section, iiiustrating a wheeledtruck frame equipped with a steering mechanism, embodying features ofthe present invention.

Figure 41 is a plan view of the steering mechanism shown in Figure 3.

Figure E is a vertical sectionalview of a portion i one of the bearingroller supports.

A steerin mechanism constructed in acsrnnnme mncmuvrsm.

Serial No. 636,137. Divided and this application filed August 13,

1926. Serial No. 128,984.

cordance with the present invention will first be described as embodiedin a power excavator of the creeping traction type. /The base or truckframe of a machine of that type is illustrated in Figures 1 and 2. Thisframe is of substantially the same construction as that fully describedin U. S. Patent No. 1,574,041 of S. R. W. M. Bager and Werner Lehman. Itcomprises a pair of longitudinal side sills 1O rigidly connected with apair of end bars '11 and a series of transverse intermediate bars 12.The intermediate bars 12 and longitudinal sills 10 constitute a supportfor a rigid casting 13 in the form of a combined rack and track memberfor rotatably supporting the head frame 14. The casting 13 is providedwith a central "hub 15 through which the usual vertical propulsion shaft16 extends and about the axis of which the head frameis permitted torevolve.

The truck frame is supported upon two sets of rollers respectivelydisposed beyond the sides of the frame, each set bein disposed to travelupon an endless tread be t 17 trained thereabout. The front rollers 18are journaled upon the ends of an axle 19 fixed to and beneath thelongitudinal sills 10. The axle 19 may, if desired, be renderedadjustable fore-and-aft in any convenient manner, to take up 'the slackin the endless tread belt. The rear rollers 20 are provided with beltengaging lugs 21 and are driven from the rear axle shaft 22, on whichthe are mounted, through clutches 23 to be hereinafter described. Theshaft 22 is journaled in bearings 22' securedto and beneath the sills 10and is driven from the vertical ropulsion shaft 16 through the usualintermediate shaft 24 and bevel gear sets 25 and 26. Each of theintermediate rollers 27 is journaled upon the end of a separate stubshaft 28 constituting part of a bracket arm 29 secured inter- The headframe 14 is rotated about the axis of the shaft 16 by means of a pinion31 which normally meshes with a fixed rack 32 extending about theperiphery of the casting 13. Pinion 31 is carried by and driven from avertical shaft 33 journaled in the head frame and actuated by the usualmechanism (not shown) carried by the frame. In this instance, the pinion31 is spl ined to the shaft 33, so as to permit lowering of the pinionout of mesh with the fixed rack 32. It will be noted that the plane ofthe rack 32 is sufliciently elevated above the truck frame to providethe necessary clearance between the extended lower end of the pinionshaft 33 and truck frame, as the head frame revolves.

The steering mechanism shown comprises a lever 34 mounted at one end 35upon a vertical pivot pin 36 so as to swing in a horizontal plane aboutan axis adjacent the pivotal axis of the head frame. Pin 36 is removablyfixed in a boss 37 formed on the rear end of a bracket plate 38, securedto and beneath the forward pair of intermediate transverse bars 12. Thelever 34 extends forwardly and upwardly above the truck frame to a pointin advance of the casting 13 and at its upper end is provided with asegmental rack 39 below the plane of the fixed rack 32 so as to meshwith the swin pinion 31 when lowered out of mesh with t e fixed rack.

tudinal axis of the truck frame.

The position of elevation of the pinion 31 may be determined by anyappropriate means under control of the operator. In the machine shown,this means comprises a lever 40 hinged at one end upon a horizontal.pivot 41 carried by the head frame and provided with a bifurcatedportion 42 having the usual pins in rotative engagement with an annulargroove 43 formed in a collar 44 fixed'to the pinion. This lever 40 alsopreferably carries a finger 45 engageable between the teeth of therack'32,when the pinion is lowered, so as to lock'the head frame againstrotation when the pinion is disengaged from the rack 32. A link 46connected with the lever 40 and extending upwardly through the floor ofthe head frame into convenient reach of the operator may be employed foradjusting the lever 40.

A pair of pull rods 47, each extending through one of the hollow bracketarms 29, are connected at their inner ends 48 to the opposite sides ofthe lever 34. Each rod 47 extends loosely through an eye 49 in theforward end of a lever 50. and at its free end is provided with a nut 51and loeknut 52 adapted to bear against this end of lever 50 when the rodis drawn inwardly by lever 34. Each of the levers 50 is mountedintermediate its end. upon a'vertical pivot53 carried b the outer end ofone of the rearward pair 0 stub shafts 28. The rear end of each lever 50is 'fiivotally connected with a collar 54 rotatably xed. upon a sleeve55 forming a part of a clutch element 56, splined upon one end of therear axle shaft 22. Each clutch element 56 is yieldabl retained ininterlocking engagement wit formed on the face of the adjacent rearroller corresponding clutch teeth 20, so that both rear rollers arenormally locked to the rear axle shaft 22 so as to rotate therewith. Inthis instance,- tliis normal closed condition of the clutches iseffected by the provision of coiled compression springs 57 each disposedwithin one of the forward i in clutch engaging position.

The exact arrangement of the springs 56,-

levers 50, and the parts directly associated therewith, forms no part ofthe present invention, being covered by claims in the main case of whichthis a division.

During normal operation. of the machine as an excavator or crane,thepini on 31 is nor mally in the upper position in mesh with the fixedrack 32 in which position swinging of the upper frame may be effected inthe usual manner by rotation of the pinion. In order to utilize theswing mechanism for steering purposes, the head frame is first swunginto such position that the pinion 31 is above the center of thesegmental rack 39 and the pinion 31 then lowered out of mesh with thefixed rack 32 into mesh with the segmental rack.

This is accomplished by depressing the link 46 and thereby forcing thelever 40 downwardly to the dotted line position indicated in Figure 2 inwhich position the tooth 45 on the lever 40 engages between the teeth ofthe fixed rack 32 to lock the head frame against rotation.

As above pointed out, the two clutches cooperating with the rear rollers20 are normally in closed condition so that these rollers normallyrotate in unison with the rear axle shaft 22, and this shaft beingdriven from the vertical propulsion shaft 16 causes a straight linetravel of the machine. A turning movement of the machine is effected byrotation of the pinion 31 in mesh with the segmental rack 39. Forinstance, rotationof pinion 31 in a clockwise direction (Fig. 1)

causes the segmental rack'39 and lever 34 to swing in a like direction.When this occurs, the pull rod 47 on the left side of the machine isdrawn inwardly, the nut 51 thereon pressing the forward end of the lever50 inwardly against the pressure of spring 57 and causing the rear endof this lever to swing outwardly sults in a turning movement of themachine cavator mounted on wheels.

ing transversely between and rigidlysecured toward the left. A turningmovement in the other direction is similarly effected by a ro-, tationof the pinion 31 in the opposite direction.

Figures 3 and 4 illustrate a similar type of steering mechanism appliedto a power ex- The truck frame of this machine is constructed insubstantially the same manner as that hereinabove described. In thisinstance, however, the front wheels 18 are journaled upon the ends of anaxle 19 rockably mounted between the bifurcations 63 of a vertical kingpin 63. The pin 63 is journaled in a rigid mounting 64 extendat itsopposite ends to a pair of plates 65. Plates 65 are secured at theiropposite ends to and between the forward transverse bar 11 and theadjacent intermediate transverse bar I 12. The rear driving wheels 20are keyed to the opposite ends of the rear axle shaft 22", journaledbeneath the longitudinal sills 10 of the truck frame and driven from thevertical propulsion shaft 16 through the intermediate shaft 24 andappropriate gearing.

The swing pinion 31 is splined upon and driven by the shaft 33 so as tobe vertically shiftable from in mesh with the fixed rack 32 into meshwith a segmental rack 39 can ried by the lever 34. The position ofelevation of this pinion is manually controlled in the mannerhereinabove pointed outb the link 46 and lever 40, lever 40 having the'nger 45 engageable between the teeth of the fixed rack 32 when in lowerposition to lock the head frame 14 against rotation.

The steering lever 34 is mounted at its either direction from a neutralintermediate position, the front axle 19 is swung about the axis of theking pin 63 for steering purposes.

Manual steering may thusbe effected by the use of a bar 62 insertable inthe hollow boss 61 carried by the lever 34. For power 7 steering,however, the pinion 31 islowered into mesh with the segmental rack 39 sothat the lever 34', and consequently the front axle,

may be swung in' response to rotation of this pinion 1 7 Provision ispreferably made for automatically locking-the front axle againsthorizontal swinging during normal operation of the machine.- For thispurpose, trip dog 68 v is provided pivoted intermediate its ends uponthe upper forward end of lever 34'. One end of this dog is provided witha tooth 69 engageable in appropriate groove 70 found in the top face 'ofthe mounting 64 so as to releasably lock the lever 34 against swinging.The other end 71 of dog 68 is fashioned to 1project into the path ofvertical movement 0 the pinion 31. A spring 72 yieldably maintains thedog 68 in looking engagement when the pinion 31 is in upper position inmesh with the rack 32. The pinion 31, however, in its downward movementinto mesh with the segmental rack 39 depresses the end 71 of the dog androcks the dog into released position.

Various changes may be made in any of the several embodiments of theinvention hereinabove described, without departing from orsacrificingany of the advantages of the invention as defined in the appendedclaims.

I claim: if EH 1. In a machine of the character described,thecombination of: a base frame; a head frame supported thereby androtatable'with respectthereto; traction means supporting said baseframe; steering mechanism; means for actuating said steering mechanism;a rack carried y the base frame; a pinion depending from the head frameand directly engaging said rack, whereby to rotate the head framerelative to the base frame; and one means whereby the rotation of saidpinion, althou h said rotation is continuous, can be renderedinoperative to effect the rotation of the head frame and operative tooperate, otherwise than by means assing through the axis of rotation ofthe liead frame, the means for actuating the steering mechanism.

2. In a machine of the character described, the combination of: a baseframe; a head frame supported thereby and rotatable with respectthereto; ,two creeping traction units supportin said base frame; wermeans;

a clutch or each traction unit, operable to connect it to the powermeans; control means for the two clutches; a rack carried by the baseframe; a pinion carried by the head frame, and rotatable by said powermeans; and means whereby the rotation of the pinion is selectivelyutilizable to rotatelthe head frame relative to the base frame, or tounclutch one clutch by the pinions rotation in one direction, or theother clutch by the pin ions rotation in the other direction.

In testimon whereof I affix my signature.

S 'ANTE R. W. M. BAGER.

